白光LED用高效红色荧光粉的控制合成及发光机理研究

Red phosphor is one of the most important parts in white solid-state light sources, and its performance affects the luminous efficiency, lifetime, color rendering index and color temperature of the white solid-state light sources straightly. Eu3+ ion-activated molybdates/tungstates are promising candidate as red phosphor for white solid-state light sources because they have broad excitation band in the near-UV region. At present, there are two problems to be resolved to improve the luminescence efficiency of these materials. One of them is how to increase the efficiency of energy absorption of host lattice by adjusting the excitation wavelength of the material; the other problem is how to increase the efficiency of energy transfer by preventing the quenching of energy in the host lattices and promoting the energy transfer from host lattices to doped Eu3+ ions. In order to solve these problems, we propose to perform an investigation on the Eu3+ ion-activated molybdates/tungstates. A series of Eu3+ ion-activated molybdates/tungstates having designed micro-structure will be synthesized and characterized. At the same time, the energy band structure and electronic structure of the host materials will be calculated according to density functional theory. The mechanism of the host lattices absorbing light in a specific wavelength region will be studied. The quenching of excitation energy in the host lattices and the energy transfer from host lattices to doped Eu3+ ions will be investigated. On this basis, an adjusting of the photoluminescence of the molybdates/tungstates phosphor and an improvement of the luminescence efficiency will be achieved. And furthermore, this investigation will provide a theoretical support to the development of new phosphor.

红色荧光粉作为固态白光光源的重要组成部分，其性能直接影响固态白光光源的流明效率，使用寿命、显色指数及色温等指标。Eu3+离子激活的钼钨酸盐在近紫外光区有较宽的激发带，是理想的红色荧光材料。对于此类材料仍有两个问题需要解决以提高其总体荧光效率：（1）如何调控基质对特定波长的激发光的吸收，提高材料对能量的吸收效率；（2）如何阻止激发能在基质晶格内的猝灭，强化基质晶格和Eu3+离子间的能量传递，提高能量的传递效率。针对这些问题，本课题拟以Eu3+离子激活的钼钨酸盐为研究对象，对具有特定微结构特征的微纳米晶材料进行控制合成；结合量子力学计算对基质材料的能带结构和电子结构进行表征。研究基质对特定波长激发光的吸收机制，以及激发能在晶格中的猝灭和传递机理。在此基础上实现对钼钨酸盐材料荧光性能的调控，提高其荧光效率，并为新材料的开发设计提供理论支持。

稀土离子激活的钨钼酸盐是一类重要的荧光材料，近年来引起了广泛的关注。但是对于影响钨钼酸盐基质对能量的吸收，以及基质晶格和激活离子间能量传递效率的因素的认识尚不深入，从而无法实现对此类材料荧光性质的精确调控。本课题针对目前钨钼酸盐荧光粉研究中存在的这些问题，以R2XO6、R6XO12、R2B2XO9等材料为研究对象，从能量吸收、传递、转移、释放过程入手，开展钨钼酸盐荧光材料的控制合成和荧光性质研究。在如下四个方面取得了相应进展：.（一）采用柠檬酸络合物法合成了Eu3+，Sm3+离子激活的R6XO12系列荧光材料前驱体，研究了焙烧温度与材料晶体结构和微观特征之间的关系，在此基础上研究了晶粒尺寸和晶格缺陷对能量吸收、传递和猝灭过程的影响。.（二）采用溶剂热法合成了Eu3+离子激活的R2XO6系列荧光材料前驱体，研究了溶剂热合成条件（包括溶剂成分、溶质浓度、pH值、溶剂热反应温度与时间）与产物晶粒尺寸和形貌之间的关系，获得了球状及棒状R2XO6微纳米粒子的控制合成条件，实现对R2XO6微纳米球、棒的可控合成。.（三）采用高温固相法合成了Eu3+、Sm3+、Tb3+离子激活的R2B2XO9系列荧光材料，研究了激活离子种类、掺杂比例对R2B2XO9荧光材料发光特性的影响，以及基质成分变化与能量传递间的关系。获得单一组分、光色可调的近紫外激发荧光材料。.（四）对R2XO6和R6XO12系列化合物进行了密度函数理论计算，获得此类晶体能带结构、轨道布居等数据，为解释实验现象提供了理论依据。.部分研究成果发表在Journal of the American Ceramics Society, Journal of Alloys and Compounds, Physica B等刊物上，已发表SCI收录学术论文6篇，申请1项国家发明专利。按计划圆满完成项目的研究内容。